KR20160029094A - Etching agent, etching method and etching agent preparation liquid - Google Patents

Abstract

The present invention relates to a method of manufacturing a semiconductor substrate in which the decomposition of hydrogen peroxide is suppressed, the lifetime of the liquid is long, and the necessity of controlling the concentration of hydrogen peroxide in the etchant is small, even when used for a semiconductor substrate having a titanium-based metal and a metal copper or copper alloy. An etching agent for a titanium-based metal, an etching method for the titanium-based metal, and an etching solution for mixing with hydrogen peroxide. (B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide, (D) a cationic chelating agent having at least one hydroxyl group and at least three carboxyl groups An etching agent for a titanium-based metal on a semiconductor substrate having a titanium-based metal and a metallic copper or a copper alloy on the titanium-based metal, and an etching agent comprising the titanium-based metal and the etching agent, To an etchant preparation liquid for use in combination with an etchant.

Description

ETCHING METHOD AND ETCHING AGENT PREPARATION LIQUID <br> <br> <br> Patents - stay tuned to the technology ETCHING AGENT, ETCHING METHOD AND ETCHING AGENT PREPARATION LIQUID

TECHNICAL FIELD The present invention relates to a titanium-based metal processing in a semiconductor substrate having titanium (hereinafter sometimes abbreviated as Ti) -based metal, and more particularly, to titanium metal, An etching agent for a titanium-based metal on a semiconductor substrate having a titanium-based metal such as an alloy and a metal copper or a copper alloy on the titanium-based metal, an etching method, and the like.

BACKGROUND ART [0002] Semiconductor devices typified by silicon semiconductors have been progressing in miniaturization and high integration in response to demands of the market, for example, high performance and miniaturization. Copper having a small wiring resistance is mainly used as a metal forming a fine wiring pattern as the wiring is miniaturized and highly integrated. As the barrier layer for such copper wiring, a metal layer (metal film) made of metal titanium, a metal layer (metal film) made of metal tungsten, and an alloy layer (alloy film) of these metals are known.

In the process of forming a metal wiring, it is necessary to etch the metal constituting such a barrier layer. Conventionally, as an etching solution for etching these metals, for example, an etching solution such as a mixed solution of hydrofluoric acid and hydrogen peroxide or a mixed solution of phosphoric acid and hydrogen peroxide Etc. have been used.

However, since hydrogen peroxide accelerates decomposition of hydrogen peroxide by, for example, metals such as copper, silver and gold, the etchant containing hydrogen peroxide has a short liquid life and needs to appropriately control the concentration of hydrogen peroxide in the etchant Which is known to have problems.

In addition to the problem that hydrogen peroxide is decomposed, an etching solution containing hydrogen peroxide is also known to oxidize the surface of the copper wiring and to corrode metallic wiring such as copper wiring.

As an etchant or an etchant noting such a problem, an etching solution (for example, Patent Document 1 or the like) for etching a TiW composed of a specific amount of hydrogen peroxide and a specific amount of phosphate, (For example, Patent Document 2) on a semiconductor substrate made of a solution containing a specific amount of hydrogen peroxide and a specific amount of a phosphonic acid-based compound (for example, Patent Document 3) An etchant for etching a tungsten and / or titanium-tungsten alloy (for example, Patent Document 4) containing at least hydrogen peroxide water and an alkali component in the presence of a metal having good conductivity for an electrode and having a pH of 7 or less, , an aqueous solution of an acidic region having a pH of not less than 3.0 and not more than 7.0, characterized by containing hydrogen peroxide, an alkali metal ion and a rust inhibitor (For example, patent document 5), an etching agent containing an alkali metal ion as a source of supply of hydrogen peroxide and a caustic alkali as an aqueous solution of an alkaline region having a pH of more than 7.0 but 8.0 or less 5), an etchant for etching a titanium or titanium alloy in the presence of a metal which should not be etched, is an etchant for etching titanium or titanium, which is an aqueous solution consisting of a specific amount of hydrogen peroxide, a specific amount of phosphoric acid, a specific amount of phosphonic acid- (For example, patent document 6), hydrogen peroxide, a phosphonic acid-based chelating agent having a hydroxyl group and a basic compound, a copper corrosion inhibitor and / or a phosphonic acid-based chelating agent having a specific amount of a hydroxyl group A semiconductor made of a solution containing at least two kinds of anionic species having no other oxidizing power Etc. panyong etchant (for example, Patent Document 7, and so on) are known.

Patent Document 1: JP-A-2000-311891 Patent Document 2: Japanese Unexamined Patent Application Publication No. 2002-155382 Patent Document 3: JP-A-2003-328159 Patent Document 4: JP-A-2004-31791 Patent Document 5: Japanese Patent Application Laid-Open No. 2005-163108 Patent Document 6: JP-A-2005-320608 Patent Document 7: Re-publication of WO2009 / 081884

According to the cleaning process using these etching liquids or etchants, it is considered that titanium or tungsten can be selectively etched without corroding the metal wiring or the like, and these etching liquids or etching agents are used for the cleaning process of the semiconductor substrate.

However, when these etchants are used for a semiconductor substrate having a titanium-based metal and a metal or copper alloy which is more usable than the titanium-based metal, since metal copper or a copper alloy is more usable than titanium, a metal copper or a copper alloy The elution amount of copper (copper oxide) from the electrolytic solution becomes too large, so that eluted copper (copper oxide) causes decomposition of hydrogen peroxide, shortening the life of the solution, and appropriately controlling the concentration of hydrogen peroxide in the etchant I have a problem. Under such background, development of an etching agent capable of suppressing the decomposition of hydrogen peroxide contained in the etching agent has been desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of manufacturing a semiconductor substrate having a titanium-based metal, a metal copper or a copper alloy, , An etching method using the etching agent for a titanium-based metal on the semiconductor substrate, the etching agent using the etching agent, and an etching solution for mixing with hydrogen peroxide.

The present invention has the following configuration.

(1) An aqueous solution containing at least the following components (A), (B), (C) and (D): a titanium-based metal and a titanium-based metal on a semiconductor substrate having a metal copper or copper alloy on the titanium- Etching agents for metals.

(A) hydrogen peroxide

(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure

(C) an alkali metal hydroxide

(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups

(2) An etching solution containing at least the following (A), (B), (C) and (D) as an aqueous solution and having a titanium metal and a metal copper or copper alloy on the titanium metal Wherein the selective etching of the titanium-based metal on the semiconductor substrate is performed.

(A) hydrogen peroxide

(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure

(C) an alkali metal hydroxide

(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups

(3) An aqueous solution containing at least the following components (B), (C) and (D), which is mixed with a solution containing (A) hydrogen peroxide, wherein the titanium- Or an etching solution for a titanium-based metal on a semiconductor substrate having a copper alloy.

(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure

(C) an alkali metal hydroxide

(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups

The etching agent of the present invention can be used in a manufacturing process of a semiconductor device, for example, a titanium-based metal such as titanium metal, a titanium-tungsten alloy, and a titanium-based metal on a semiconductor substrate having a metal copper or a copper alloy on the titanium- Etching process. Even when used in such a semiconductor substrate, the decomposition of hydrogen peroxide is suppressed, so that the effect of the long lifetime of the etching agent and the need to control the concentration of hydrogen peroxide in the etching agent is small.

The etching method of the present invention is also an effective method for etching a titanium-based metal on a semiconductor substrate having a titanium-based metal and a metal copper or copper alloy on top of the titanium-based metal. By using the etching agent of the present invention, It is difficult to cause a change in the concentration of hydrogen peroxide in the composition. Therefore, it is possible to stably obtain a semiconductor substrate in which the etching rate is stable and, moreover, a desired amount of the titanium-based metal is etched.

In addition, the etching solution of the present invention can be used as the etching solution of the present invention by mixing with hydrogen peroxide. For example, when the etching solution of the present invention is used, hydrogen peroxide and the etching solution are prepared for use, And the liquid life of the etching agent can be made longer.

As a result of intensive research to achieve the above object, the present inventors have found that among the copper corrosion inhibitors known in the art, by using an organic acid having at least one hydroxyl group and at least three carboxyl groups, (Copper oxide) contained in the copper chelate can be minimized. Among the various chelating agents, the use of a phosphonic acid chelating agent having a nitrogen atom in the structure enables copper to be eluted from metal copper or a copper alloy, Specifically, it has been found that copper oxide is chelated to inhibit decomposition of hydrogen peroxide by copper (copper oxide). That is, by combining a phosphonic acid chelating agent having a nitrogen atom in its structure with an organic acid having at least one hydroxyl group and at least three carboxyl groups, the elution of copper (copper oxide) from metal copper or a copper alloy is suppressed, Even if copper (copper oxide) is eluted, adverse effects on hydrogen peroxide can be reduced by chelating copper (copper oxide). It has been found that the titanium-based metal on the semiconductor substrate having the titanium-based metal and the metallic copper or the copper alloy can be stably etched because decomposition of the hydrogen peroxide can be suppressed by such a mechanism, and the present invention has been accomplished .

In the present invention, the titanium-based metal (Ti-based metal) refers to a metal containing Ti as a main component such as Ti or a titanium-tungsten alloy (TiW alloy).

- Etching agent for titanium metal of the present invention -

The etching agent of the present invention comprises at least (A) a hydrogen peroxide, (B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide, and (D) at least one hydroxyl group and at least three carboxyl groups It is an aqueous solution containing an organic acid.

(A) The hydrogen peroxide is used for the purpose of oxidizing the Ti-based metal and facilitating the dissolution of the Ti-based metal by the alkali metal hydroxide, for example, a commercially available hydrogen peroxide solution. More specifically, for example, commercially available 35% or 60% hydrogen peroxide may be hydrogen peroxide diluted with purified water such as distilled water or deionized water, ultrapure water or the like to a concentration described later.

The phosphonic acid-based chelating agent having a nitrogen atom in the structure (B) forms a water-soluble complex to be added to the oxidized Ti-based metal, facilitates dissolution of the Ti-based metal, More specifically, it is used for the purpose of suppressing decomposition of hydrogen peroxide by copper (copper oxide) by chelating copper oxide. Examples of such a phosphonic acid chelating agent include those represented by the following general formula [1] or [2].

Wherein Q represents a hydrogen atom or a group represented by -R ² -PO ₃ H ₂ , R ¹ and R ² each independently represent an alkylene group, Y represents a hydrogen atom, -R ² -PO ₃ H ₂ Or a group represented by the following general formula [3], and m represents 0 or 1. However, when Y is a group represented by the following general formula [3], m is 1.)

Wherein Q and R &lt; ² &gt; are as defined above.

R ³ and R ⁴ each independently represent an alkylene group having 1 to 4 carbon atoms; n represents an integer of 1 to 4; at least four of Z ¹ to Z ⁴ and n Z ⁵ are a phosphonic acid group And the remainder represents an alkyl group.

Examples of the alkylene group represented by R ¹ in the general formula [1] include a linear or branched alkylene group having 1 to 12 carbon atoms, and specific examples thereof include a methylene group, an ethylene group, a propylene group, a trimethylene group, A methylene group, a tetramethylene group, a 2-methylpropylene group, a 2-methyltrimethylene group, an ethylethylene group, a pentamethylene group, a 2,2-dimethyltrimethylene group, a 2-ethyltrimethylene group, a hexamethylene group, An octamethylene group, a 2-ethylhexamethylene group, a nonanemethylene group, a decamethylene group, an undecamethylene group, a dodecamethylene group and the like. Of these, a methylene group, an ethylene group, a propylene group , A trimethylene group, an ethylmethylene group, a tetramethylene group, a 2-methylpropylene group, a 2-methyltrimethylene group, an ethylethylene group, a pentamethylene group, a 2,2-dimethyltrimethylene group, Hexamethylene group and the like having 1 to 6 carbon atoms such as straight or branched Killen group is preferable, and among them is more preferably an alkylene group having 2 ethylene.

Examples of the alkylene group represented by R ² in the general formulas [1] and [3] include linear or branched alkyl groups having 1 to 10 carbon atoms. Specific examples thereof include a methylene group, an ethylene group, A methylene group, an ethylmethylene group, a tetramethylene group, a 2-methylpropylene group, a 2-methyltrimethylene group, an ethylethylene group, a pentamethylene group, a 2,2-dimethyltrimethylene group, A methylene group, an ethylene group, an alkylene group having 1 to 2 carbon atoms, and the like. Of these, a methylene group and an ethylene group are preferable. Of these, a methylene group, an ethylmethylene group, a 2-ethylhexamethylene group, More preferably a methylene group which is an alkylene group having 1 to 1 carbon atoms.

In the general formulas [1] and [3], Q is more preferably a group represented by -R ² -PO ₃ H ₂ .

In the general formula [1], Y is more preferably a group represented by -R ² -PO ₃ H ₂ or a group represented by the general formula [3], and in particular, a group represented by -R ² -PO ₃ H ₂ is particularly preferable desirable.

In the general formula [1], m is usually 0 or 1, preferably 0. [ When m is 0, there is no group represented by R ¹ in the general formula [1], indicating that a group represented by Y and a nitrogen atom are directly bonded to each other.

Examples of the alkylene group having 1 to 4 carbon atoms represented by R ³ and R ⁴ in the general formula [2] include a linear or branched alkylene group, and specific examples thereof include a methylene group, an ethylene group, a propylene group, a trimethylene Methylethylene group, 2-methyltrimethylene group, 2-methyltrimethylene group and ethylethylene group. Of these, an ethylene group which is an alkylene group having 2 carbon atoms is preferable.

In the general formula [2], n is usually an integer of 1 to 4, preferably an integer of 1 to 2, and more preferably 1.

Examples of the alkyl group in the alkyl group represented by Z ¹ to Z ⁵ and the "alkyl group having a phosphonic acid group" in the general formula [2] include a linear or branched alkyl group having 1 to 4 carbon atoms, Methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group and t-butyl group. In the above specific examples, n- represents a normal-sieve, s- represents a sec-sieve, and t- represents a tert-sieve.

The number of phosphonic acid groups in the "alkyl group having a phosphonic acid group" represented by Z ¹ to Z ⁵ in the general formula [2] is usually 1 to 2, preferably 1.

Examples of the alkyl group having a phosphonic acid group represented by Z ¹ to Z ⁵ in the general formula [2] include a straight or branched alkyl group having 1 to 4 carbon atoms and one or two phosphonic acid groups, (Mono) phosphono-n-propyl group, a (mono) phosphono-n-butyl group, a (Mono) phosphono-s-butyl group, a (mono) phosphono-t-butyl group, a diphosphonomethyl group, a diphosphonoethyl group, a diphosphono- Butyl group, a diphosphono-isopropyl group, a diphosphono-n-butyl group, a diphosphono isobutyl group, a diphosphono-s-butyl group and a diphosphono- (Mono) phosphonomethyl group or (mono) phosphonoethyl group which is an alkyl group having one phosphonic acid group as 2, and among them, a phosphonic acid group The alkyl group (mono), a phosphono group with one is more preferable. In the above specific examples, n- represents a normal-sieve, s- represents a sec-sieve, and t- represents a tert-sieve.

In the general formula [2], it is preferable that all of Z ¹ to Z ⁴ and n Z ⁵ are an alkyl group having a phosphonic acid group as Z ¹ to Z ⁵ .

Specific examples of the phosphonic acid chelating agent having a nitrogen atom in the structure (B) include ethylamino bis (methylenephosphonic acid), dodecylaminbis (methylenephosphonic acid), nitrilotris (methylenephosphonic acid) [NTPO Propylene diamine bis (methylene phosphonic acid), and 1,3-propylene diamine bis (methylene phosphonic acid)], ethylene diamine bis (methylene phosphonic acid) [EDDPO], propanediamine bis Propylene diamine tetra (methylene phosphonic acid) [EDTPO], ethylenediamine tetra (ethylene phosphonic acid), propanediamine tetramethylene phosphonic acid [PDTMP] [1,2-propylene diamine tetra Phosphonic acid chelating agents represented by the general formula [1] such as tetra (methylene phosphonic acid) and 1,6-hexamethylenediamine tetra (methylene phosphonic acid); For example, diethylenetriaminepenta (methylenephosphonic acid) [DEPPO], diethylenetriaminepenta (ethylenephosphonic acid), triethylenetetraminehexa (methylenephosphonic acid), triethylenetetraminehexa (ethylenephosphonic acid), etc. (Methylenephosphonic acid) [NTPO], ethylenediaminetetra (methylenephosphonic acid) [EDTPO], diethylene triol (methylenephosphonic acid), and the like can be given. Among them, nitrile tris (methylenephosphonic acid) [NTPO] and diethylenetriamine penta (methylenephosphonic acid) [DEPPO] are more preferable, and among them, more preferred are aminopenta (methylenephosphonic acid) [DEPPO] Nitrile tris (methylenephosphonic acid) [NTPO] is particularly preferable. These preferred phosphonic acid-based chelating agents are preferable chelating agents in that they are more effective in inhibiting the decomposition of hydrogen peroxide than other phosphonic acid-based chelating agents. These phosphonic acid chelating agents may be used singly or in combination of two or more kinds of phosphonic acid chelating agents. These phosphonic acid chelating agents, for example, phosphonic acid salts such as alkali metal salts of phosphonic acid, and phosphonic acid derivatives such as phosphonic acid esters may also be used. These phosphonic acid-based chelating agents may be commercially available ones or may be those appropriately synthesized by known methods. Commercially available phosphonic acid chelating agents include, besides the phosphonic acid-based chelating agents, Deionized water, and purified water such as deionized water, ultrapure water, and the like, and a phosphonic acid-based chelating agent containing such water can be used without any problem.

The alkali metal hydroxide (C) is used to adjust and maintain the pH of the etching agent of the present invention to a desired range and dissolve the Ti-based metal oxidized by hydrogen peroxide. Examples of such alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide. Particularly, lithium hydroxide, sodium hydroxide and potassium hydroxide are preferable, and lithium hydroxide, sodium hydroxide More preferable. These preferable alkali metal hydroxides have a higher etching rate of the Ti-based metal (having a high Ti / Cu dissolution rate ratio) to metal copper or copper alloy as compared with other alkali metal hydroxides, Lt; RTI ID = 0.0 &gt; alkali metal &lt; / RTI &gt; hydroxide. These alkali metal hydroxides may be used alone or in combination of two or more kinds of alkali metal hydroxides. Commercially available alkali metal hydroxides may be used.

(D) The organic acid having at least one hydroxyl group and at least three carboxyl groups is used for the purpose of inhibiting elution of copper from metallic copper or copper alloy. That is, an organic acid having at least one hydroxyl group and at least three carboxyl groups is used as a copper corrosion inhibitor. Examples of such organic acids having at least one hydroxyl group and at least three carboxyl groups include citric acid and the like. These organic acids may be used singly or in combination of two or more kinds of organic acids. Commercially available organic acids may be used.

The etching agent of the present invention is water because it is an aqueous solution. The water is not particularly limited as long as it does not adversely affect the semiconductor substrate in the manufacturing process of the semiconductor device. Specific examples of the water include purified water such as distilled water and deionized water, ultrapure water and the like, among which ultrapure water is preferable. Ultrapure water is preferable water in that it contains little impurities and does not adversely affect the semiconductor substrate in the manufacturing process of the semiconductor device.

The etching agent of the present invention may contain (E) a pH adjusting agent, (F) a surfactant and the like as other components as necessary in addition to the constituent components (A), (B), (C) and (D).

(E) The pH adjusting agent may be appropriately added in view of the ability to adjust and maintain the pH of the etching agent of the present invention to a desired range. Examples of the (E) pH adjusting agent include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, boric acid, hydrofluoric acid and carbonic acid. These pH adjusters may be used alone or in combination of two or more kinds of pH adjusters. Commercially available pH adjusting agents may be used.

(F) The surfactant may be appropriately added in view of improving the wettability of the etching agent of the present invention on the surface of the semiconductor substrate. Examples of such (E) surfactants include cationic surfactants, anionic surfactants, nonionic surfactants, and amphoteric surfactants. Specific examples of the cationic surfactant include primary to tertiary alkylamine salts such as monostearyl ammonium chloride, distearyl ammonium chloride, and tristearyl ammonium chloride; For example, modified aliphatic polyamines such as polyethylene polyamines. Specific examples of the anionic surfactant include, for example, alkylcarboxylic acid sodium salt, alkylcarboxylic acid potassium salt, alkylcarboxylic acid ammonium salt, alkylbenzenecarboxylic acid sodium salt, alkylbenzenecarboxylic acid potassium salt, alkylbenzenecarboxylate Sodium polyoxyalkylene alkyl ether carboxylate, potassium polyoxyalkylene alkyl ether carboxylate, ammonium polyoxyalkylene alkyl ether carboxylate, sodium salt of N-acyl sarcosinate, N-acyl sarcosine Anionic surfactants having a carboxyl group in the molecule such as potassium salt of potassium phosphate, potassium salt of potassium phosphate, sodium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt of potassium salt. For example, an alkylsulfonic acid such as an alkylsulfonic acid sodium salt, an alkylsulfonic acid potassium salt, an alkylsulfonic acid ammonium salt such as dodecylbenzenesulfonic acid, an alkylbenzenesulfonic acid such as sodium dodecylbenzenesulfonate Potassium salt of alkylbenzenesulfonic acid such as sodium salt such as potassium dodecylbenzenesulfonate, ammonium salt of alkylbenzenesulfonic acid such as ammonium dodecylbenzenesulfonate, sodium salt of alkylnaphthalenesulfonic acid, potassium salt of alkylnaphthalenesulfonic acid Salts of alkylnaphthalenesulfonic acid ammonium salts, polyoxyalkylene alkyl ether sulfonic acid sodium salts, polyoxyalkylene alkyl ether sulfonic acid potassium salts, polyoxyalkylene alkyl ether sulfonic acid ammonium salts, N-methyl-N-acyltaurine sodium salt , N-methyl-N-acyltaurine potassium salt, N-methyl-N-acyltaurine ammonium salt, sodium dialkylsulfosuccinate such as sodium dioctylsulfosuccinate, for example, potassium dioctylsulfosuccinate , Anionic surfactants having a sulfonic acid group in the molecule such as dialkylsulfosuccinic acid ammonium salts such as ammonium dioctylsulfosuccinate; For example, an alkylsulfuric acid sodium salt such as sodium laurylsulfate, an alkylsulfuric acid potassium salt such as potassium laurylsulfate such as an alkylammonium salt such as ammonium laurylsulfate, and the like; an anionic surfactant having a sulfate group in the molecule; For example, sodium alkylphosphonate, potassium alkylphosphonate, ammonium alkylphosphonate, sodium alkylbenzenephosphonate, potassium alkylbenzenephosphonate, ammonium alkylbenzenesulfonate, sodium polyoxyalkylene alkylether phosphonate , Anionic surfactants having a phosphonic acid group in the molecule such as polyoxyalkylene alkyl ether phosphonate potassium salt and polyoxyalkylene alkyl ether phosphonate ammonium salt. Specific examples of the nonionic surfactant include polyoxyethylene alkyl ethers such as polyoxyethylene stearyl ether, polyoxyethylene alkenyl ethers such as polyoxyethylene oleyl ether, and polyoxyethylene alkenyl ethers such as polyoxyethylene nonylphenyl Polyoxyalkylene alkylphenyl ethers such as ether, polyoxyalkylene glycols such as polyoxypropylene polyoxyethylene glycol, polyoxyethylene monoalkylates such as polyoxyethylene monostearate, Bispolyoxyethylene alkylamine such as bispolyoxyethylene stearylamine, bispolyoxyethylene alkylamide such as bispolyoxyethylene stearylamide, alkylamine such as N, N-dimethylalkylamine oxide Oxide and the like. Specific examples of the amphoteric surfactant include carboxybetaines such as alkyl-N, N-dimethylaminoacetic acid betaine and alkyl-N, N-dihydroxyethylaminoacetic acid betaine; Sulfobetaines such as alkyl-N, N-dimethylsulfoethylene ammonium betaine; And imidazolidinium betaines such as 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine. These surfactants may be used singly or in combination of two or more kinds of surfactants. A commercially available surfactant may be used.

(A), (B), (C) and (D) from the viewpoint that the Ti-based metal can be etched without adversely affecting the members constituting the semiconductor element, Sometimes it is desirable not to include it. Means that the other component does not contain an amount of more than the amount capable of adversely affecting the member or the like (hereinafter referred to as " component (A), component (B) It says. That is, it does not exclude even those containing an extremely small amount of other components (those containing an extremely small amount of other components), and do not substantially contain other components.

(C) an alkali metal hydroxide and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups in the structure of (A) hydrogen peroxide of the etching agent of the present invention, (B) , And the pH adjuster (E) and the surfactant (F), which are auxiliary components, are preferably adjusted to the following weight percent concentrations.

(A) The concentration by weight of hydrogen peroxide is usually 10 to 33% by weight, preferably 10 to 30% by weight, based on the total weight of the etching agent (A). If the concentration by weight of the component (A) is less than 10% by weight, the etching rate of the Ti-based metal may be very slow. If the concentration by weight of the component (A) exceeds 33% by weight, hydrogen peroxide may be decomposed by copper (copper oxide) eluted from metal copper or a copper alloy, thereby causing abnormal heat generation due to decomposition of hydrogen peroxide.

The weight% concentration of the phosphonic acid-based chelating agent having a nitrogen atom in the structure (B) is usually from 0.05 to 5% by weight, preferably from 0.05 to 3% by weight, more preferably from 0.05 to 3% by weight, And preferably 0.1 to 3% by weight. (Chelating) copper (copper oxide) eluted from metallic copper or a copper alloy can not be captured (chelated) when the weight% concentration of the copper (B) is less than 0.05 wt% ) May decompose hydrogen peroxide and cause abnormal heat generation due to decomposition of hydrogen peroxide. If the concentration by weight of the component (B) exceeds 5% by weight, the selectivity of the Ti-based metal to be etched may deteriorate.

The weight% concentration of alkali metal hydroxide (C) is usually 0.2 to 5% by weight, preferably 0.2 to 4% by weight, more preferably 0.3 to 4% by weight, based on the total weight of the etchant (C) to be. If the concentration by weight of the component (C) is less than 0.2% by weight, the etching rate of the Ti-based metal may be lowered. If the concentration by weight of the component (C) exceeds 5% by weight, the hydrogen peroxide may undergo self-decomposition to cause abnormal heat generation due to self-decomposition of hydrogen peroxide.

(D) The weight% concentration of the organic acid having at least one hydroxyl group and at least three carboxyl groups is usually 0.01 to 5% by weight, preferably 0.03 to 3% by weight, based on the total weight of the etchant (D) %, More preferably 0.04 to 1% by weight. When the concentration by weight of the component (D) is less than 0.01% by weight, copper tends to be eluted from the copper or copper alloy. If the concentration by weight of (D) exceeds 5% by weight, the selectivity of the Ti-based metal to be etched may be lowered.

(E) The weight% concentration of the pH adjusting agent is usually 0.05 to 4% by weight, preferably 0.2 to 3% by weight, based on the total weight of the etchant (E). If the concentration by weight of the component (E) exceeds 4% by weight, the etching rate of the Ti-based metal may decrease.

(F) The weight% concentration of the surfactant is usually 0.001 to 1% by weight, preferably 0.01 to 0.5% by weight, based on the total weight of the etching agent (F). If the concentration by weight of the component (F) exceeds 1% by weight, the etching rate of the Ti-based metal may be lowered.

The etching agent of the present invention is preferably a neutral to alkaline aqueous solution, more preferably an aqueous solution having a pH of 7 to 10, more preferably an aqueous solution having a pH of 7.5 to 9.5, more preferably 8.0 to 9.5 Is particularly preferred. If the pH of the aqueous solution is less than 7, the etching rate of the Ti-based metal may be lowered, (B) the complex-forming ability of the phosphonic acid chelating agent having nitrogen atoms in the structure may deteriorate, May be deteriorated. If the pH of the aqueous solution is more than 10, the stability of hydrogen peroxide may be lowered, causing self-decomposition of hydrogen peroxide to cause abnormal heat generation due to the self-decomposition of hydrogen peroxide. However, there is a possibility that the selectivity of the Ti- (Si) substrate and the like. Further, by adjusting the pH of the etching agent of the present invention within such a preferable range, the etching rate by the etching agent can be set to a desired speed, and most of the metal copper or copper alloy is not etched, and only the Ti-based metal is etched The semiconductor substrate can be stably obtained. Further, the pH adjustment may be carried out mainly by adjusting the content of (C) alkali metal hydroxide.

The pH of the etchant of the present invention is measured by using a commercially available pH meter according to JIS Z8802-1984 without dilution.

(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide, and (D) at least one hydroxyl group and at least three carboxyl groups (E) a pH adjuster, and (F) a surfactant if necessary. The preparation method itself is not particularly limited. Specific examples of the preparation method include, for example, in ultrapure water, (B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups (F) a surfactant is added if necessary, (E) a pH adjusting agent is added to the solution to adjust the pH, and the solution is stirred to form a homogeneous aqueous solution. The etching agent of the present invention thus prepared may be subjected to a filtration treatment or the like before use.

Examples of the stirring / mixing apparatus used when preparing the etching agent of the present invention include an agitator and a disperser. Examples of the stirrer include a mechanical stirrer and a magnetic stirrer. Examples of the dispersing machine include a homogenizer, an ultrasonic dispersing machine, a ball mill, and a bead mill.

- etching method of the present invention -

The etching method of the present invention is an etching method comprising (A) a hydrogen peroxide, (B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide, and (D) a compound having at least one hydroxyl group and at least three carboxyl groups Characterized in that selective etching of the titanium-based metal on the semiconductor substrate having the titanium-based metal and the metallic copper or the copper alloy on the titanium-based metal is carried out by using an etching agent which is an aqueous solution containing an organic acid. That is, the etching method of the present invention is characterized by using the etching agent of the present invention, and the etching method itself is not particularly limited.

As a specific example of the etching method of the present invention, first, the etching agent of the present invention prepared in the predetermined concentration range by the aforementioned preparation method is prepared. Subsequently, the Ti-based metal can be selectively etched, for example, by immersing a Ti-based metal and a semiconductor substrate having a metal copper or copper alloy on the Ti-based metal in the etching agent of the present invention. The etching method is not limited to the immersion method. In addition to the immersion method, in addition to the immersion method, a spin (dropping) method of dropping the etching agent of the present invention while rotating the semiconductor substrate, a spraying method of spraying the etching agent of the present invention Adoption of the forms in this field is appropriate.

In the etching method of the present invention, the processing method of the semiconductor substrate may be either a sheet-like method or a batch method. The sheet-laying method is generally a method of processing semiconductor substrates one by one, and the arrangement method is generally a method of simultaneously processing a plurality of semiconductor substrates.

In the etching method of the present invention, the etching temperature is not particularly limited as long as it is an etching temperature in this field. A specific example of the etching temperature is, for example, 10 to 50 占 폚.

Since the etching time in the etching method of the present invention depends on the shape and thickness of the Ti-based metal to be etched, it can not be said uniformly. For practical use, for example, it is usually 30 seconds to 1 hour, preferably 1 to 30 minutes , More preferably from 1 to 10 minutes.

- The etchant preparation liquid of the present invention -

(C) an alkali metal hydroxide; and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups in the structure (B). The etching solution contains at least a phosphonic acid chelating agent having a nitrogen atom in the structure (A) an aqueous solution containing (A) hydrogen peroxide, which is mixed with a solution comprising a titanium-based metal and a metal copper or copper alloy on top of the titanium-based metal to prepare an etching agent for a titanium- will be.

That is, the etching solution of the present invention is used for preparing the etching solution of the present invention by mixing with (A) a solution containing hydrogen peroxide. In the supply mode of the etching solution of the present invention, Refers to an aqueous solution containing other than (A) a solution comprising hydrogen peroxide.

As described above, the etching agent of the present invention can be obtained by mixing (A) a solution containing hydrogen peroxide, (B) a phosphonic acid chelating agent having a nitrogen atom in the structure (B), (C) an alkali metal hydroxide, and A solution of an etching agent which is an aqueous solution containing an organic acid having at least three carboxyl groups and a hydroxyl group, and by using them as an etching agent of the present invention when they are used at the time of using the etching agent of the present invention, decomposition of hydrogen peroxide is further promoted And the liquid life of the etching agent can be further extended. Therefore, it is preferable to mix the solution of the etching solution of the present invention with the solution containing (A) hydrogen peroxide immediately before using the etching agent of the present invention.

(B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups in the composition of the etching solution of the present invention The weight% concentration of the constituent components is preferably such that the weight% concentration of each of the constituent components (B), (C) and (D) is in the range of the above-mentioned weight% when the composition is mixed with the solution containing (A) hydrogen peroxide, There is no particular limitation as long as the concentration of the component (A) is adjusted. For example, an etching solution containing each component whose concentration is adjusted to the range shown below is prepared, and the solution containing the component (A) The etching agent of the present invention may be prepared.

The weight% concentration of the phosphonic acid chelating agent having a nitrogen atom in the structure (B) of the etching solution of the present invention is usually from 1 to 10% by weight, preferably from 1 to 10% by weight, based on the total weight of the etching solution, , Preferably 1 to 8 wt%, and more preferably 2 to 6 wt%.

The weight% concentration of the alkali metal hydroxide (C) in the etching solution of the present invention is usually 4 to 10% by weight, preferably 5 to 10% by weight, in terms of% by weight based on the total weight of the etching solution %, More preferably 6 to 10 wt%.

The weight% concentration of (D) the organic acid having at least one hydroxyl group and at least three carboxyl groups in the etchant preparation liquid of the present invention is usually from 0.2% by weight to (D) 10% by weight, preferably 0.2 to 8% by weight, more preferably 0.4 to 6% by weight.

The etching solution of the present invention may contain (E) a pH adjusting agent, (F) a surfactant, and the like as other components as necessary in addition to the components (B), (C) and (D). These weight% concentrations in the etching solution of the present invention are such that when the etching solution of the present invention is mixed with (A) a solution containing hydrogen peroxide, the weight% concentration of each component (E) and (F) There is no particular limitation as long as it is a concentration.

The etching solution preparation liquid containing the components (B), (C) and (D) adjusted to such a weight percent concentration and the components (E) and (F) if necessary is usually 20 to 35% by weight, (A) 20 to 30% by weight, more preferably 25 to 30% by weight, of hydrogen peroxide.

(A) solution (first solution) containing hydrogen peroxide and the etching solution (second solution) of the present invention [first solution: second solution] is usually 50:50 to 95: 5, preferably 60:40 to 90:10, and more preferably 70:30 to 80:20.

(A) a method of mixing the solution containing hydrogen peroxide with the solution of the etching solution of the present invention, that is, (A) a solution comprising hydrogen peroxide and the etching solution of the present invention using the etching solution of the present invention May be suitably employed. The stirring / mixing apparatus used in the preparation may be the stirring / mixing apparatus described above.

The pH of the solution containing the hydrogen peroxide (A) and the solution of the etching solution of the present invention is not particularly limited, and the pH at the time of mixing these solutions, that is, the pH at the time of mixing them into the etching solution of the present invention, The above-mentioned pH need only be attained. In other words, the pH of the solution containing the (A) hydrogen peroxide and the etching solution of the present invention is usually from neutral to alkaline, preferably from 7 to 10, more preferably from 7.5 to 9.5, More preferably, the pH of the solution of the etching solution of the present invention and the solution containing (A) hydrogen peroxide is adjusted so as to be an etching agent of the present invention having a pH of from 8.0 to 9.5.

The concentration of the components (B), (C) and (D) in the etching solution of the present invention is preferably such that the weight% concentration of each component (B) For example, 10 times to 100 times as high as the concentration of the solution. The etching solution of the present invention having such a high concentration component can be diluted with water or the like at the time of preparation or the like.

- a semiconductor substrate according to the present invention;

A semiconductor substrate according to the present invention is a semiconductor substrate having at least a Ti-based metal on an upper surface of a wafer constituting a semiconductor substrate, and further comprising a metal copper or a copper alloy on the Ti-based metal. Specific examples of the wafers constituting the semiconductor substrate include silicon (Si) wafers, silicon carbide (SiC) wafers, silicon wafers such as resin wafers (glass epoxy wafers) , Gallium arsenide (GaAs) wafers, and indium phosphide (InP) wafers. Examples of the silicon (Si) wafer include an n-type silicon (Si) wafer doped with a pentavalent atom such as phosphorus (P), arsenic (As), antimony (Sb) ) The wafer may be a p-type silicon (Si) wafer doped with a trivalent atom such as boron (B) or gallium (Ga). The silicon (Si) of the silicon (Si) wafer may be, for example, amorphous silicon, single crystal silicon, polycrystalline silicon, or polysilicon. Among such wafers, the etching agent and the etching method of the present invention are suitably used for a wafer made of a silicon material such as a silicon (Si) wafer, a silicon carbide (SiC) wafer, and a resin-based wafer (glass epoxy wafer) .

The semiconductor substrate according to the present invention may have an insulating film on the wafer. Specific examples of the insulating film include a silicon oxide film such as silicon dioxide (SiO ₂ ) film and tetraethylorthosilicate tetraethyl (OC ₂ H ₅ ) ₄ film (TEOS film), for example, silicon nitride (Si ₃ N ₄ ) (SiOC film, SiC film, etc.), and silicon nitride films such as silicon carbide silicon nitride (SiNC), for example, a low dielectric constant (low-k) film

The semiconductor substrate according to the present invention has at least a Ti-based metal, but the Ti-based metal may be made of metal Ti alone or an alloy (Ti-based alloy) made of metal Ti and another metal as described above. The Ti-based alloy referred to herein is an alloy containing Ti as a main component and includes, for example, at least one metal selected from the group consisting of tungsten (W), nickel (Ni) and aluminum (Al) Specific examples of such alloys include titanium-tungsten alloys (TiW alloys), titanium-nickel alloys (TiNi alloys), and titanium-aluminum alloys (TiAl alloys). The etchant and etching method of the present invention is suitably used for metal Ti or a titanium-tungsten alloy (TiW alloy).

The Ti-based metal according to the present invention is a metal constituting a barrier metal, an adhesion layer, or the like in the semiconductor substrate according to the present invention.

The semiconductor substrate according to the present invention has metal copper or a copper alloy on the Ti-based metal, but the metal copper or copper alloy is a metal constituting the adhesion layer, the wiring, the bump, or the like.

In the case where the metal copper or copper alloy according to the present invention is a copper wiring or a copper alloy wiring, the copper alloy wiring referred to herein is a copper alloy wiring mainly composed of copper, and examples thereof include magnesium (Mg), manganese (Mn) Ni), and copper alloy wiring made of copper. Specific examples of such copper alloy wiring include copper-magnesium alloy wiring (CuMg alloy wiring), copper-manganese alloy wiring (CuMn alloy wiring), and copper-nickel alloy wire (CuNi alloy wiring).

When the Ti-based metal according to the present invention is an adhesion layer, the semiconductor substrate according to the present invention may have a barrier metal made of a metal other than Ti-based metal. Specific examples of the barrier metal include tantalum (Ta), tantalum nitride (Ta), and the like.

The semiconductor substrate according to the present invention may have a lead (Pb) pre-solder bump. Examples of the metal constituting the lead (Pb) free solder bump include copper (Cu), tin (Sn), aluminum (Al), nickel (Ni), zinc (Zn), silver (Ag) ), Indium (In), antimony (Sb), bismuth (Bi), and the like. When the lead (Pb) free solder bump is a bump made of metal copper or a copper alloy, the metal constituting the bump may be a bump made of copper or a copper alloy bump made of at least one metal selected from tin (Sn) . Specific examples of such copper alloy bumps include copper-tin alloy bumps (CuSn alloy bumps) and the like.

In the case where the semiconductor substrate according to the present invention has a bump made of metal copper or a copper alloy, the wiring may be a wiring made of metal copper or a metal other than copper alloy. Examples of the metal constituting the wiring include aluminum (Al) and gold (Au). Specific examples of such wirings include aluminum (Al) wiring, gold (Au) wiring, and the like.

In the case where the semiconductor substrate according to the present invention has a lead (Pb) pre-solder bump, the semiconductor substrate is preferably made of nickel (Ni), palladium (Pd ), Copper (Cu), or the like.

The method for forming the barrier metal, the adhesion layer, the metal wiring, the lead (Pb) free solder bump, and the conductor / adhesive portion is not particularly limited as long as it is a method usually performed in this field. Specifically, A barrier metal, a contact layer, a metal wiring, a lead (Pb) pre-solder bump, and a conductor / adhesive portion are formed by plating or chemical vapor deposition after forming a circuit using a resist or the like on a wafer constituting a semiconductor substrate do.

Example

Hereinafter, the present invention will be described in detail based on examples and comparative examples, but the present invention is not limited to these examples. In the following examples, percentages are by weight (w / w)% unless otherwise specified.

Example 1: Preparation of etching agent of the present invention -1

To the ultrapure water were added hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itaramachi Japan KK) (Manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsuya Co., Ltd.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was used as the etching first.

Comparative Example 1: Preparation of Comparative Etching Agent-1

Hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), 1-hydroxyethane-1,1-bis (phosphonic acid) (60% aqueous solution) (manufactured by Wako Pure Chemical Industries, Ltd.) was added to ultrapure water, Potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsu Co., Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was used as the etching second.

Comparative Example 2: Preparation of Comparative Etching Agent-2

(Manufactured by Wako Pure Chemical Industries, Ltd.), ethylenediamine tetraacetic acid (manufactured by Wako Pure Chemical Industries, Ltd.), potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsu Kogyo Co., Ltd.) ) Was added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was used as an etching third.

The composition (component and% by weight) of the etchant of Example 1 and Comparative Examples 1 to 2 is shown in Table 1. [

Example 1 Comparative Example 1 Comparative Example 2 Etching 1 Etching second Etching third Hydrogen peroxide (% by weight) 24.5 24.5 24.5 Chelating agent
(weight%) DEPPO
1.5 HEDPO
1.5 EDTA
1.5 Potassium hydroxide (% by weight) 3.0 3.0 3.0 Citric acid (% by weight) 0.1 0.1 0.1 Water (% by weight) 70.9 70.9 70.9 DEPPO: Diethylene triamine penta (methylene phosphonic acid)
HEDPO: 1-hydroxyethane-1,1-bis (phosphonic acid)
EDTA: Ethylenediamine tetraacetic acid

Experimental Examples 1 to 3: Immersion test of Etching Nos. 1 to 3

Each of the etching agents obtained in Example 1 and Comparative Examples 1 and 2 was placed in a container made of polypropylene and heated to 40 ° C. To the etching agent, a 1 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a 2 cm x 2 cm copper plate Manufactured by Metallic Co., Ltd.) were immersed for one hour at the same time for 300 minutes. During the etching, 100 μL was sampled at predetermined times (30, 60, 180, 300 minutes) for analyzing the metal content and 100 μL was sampled for analysis of hydrogen peroxide.

Each of the sampled etchants used for analyzing the metal content was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the amounts of dissolution of metallic titanium and metallic copper per unit area of the titanium plate and copper plate, and the etching rates of titanium and copper were calculated. The results are shown in Table 2.

Each of the etching agents sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method using 0.02 mol / L potassium permanganate. The results are shown in Table 3.

These experimental examples are experiments in which a titanium plate and a copper plate were continuously immersed for one time each for a maximum of 300 minutes. In this experimental example, in the actual use of the etching agent, a model experiment in which a method of continuously immersing a plurality of semiconductor substrates , And the etch rate and the decomposition rate of hydrogen peroxide when the same etchant was continuously used for etching a plurality of semiconductor substrates for a maximum of 300 minutes.

time
(minute) Experimental Example 1
Etching 1 Experimental Example 2
Etching second Experimental Example 3
Etching third Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) 30 158 1.8 120 1.3 165 0.4 60 145 1.2 128 1.3 164 0.4 180 149 1.0 141 1.2 180 0.5 300 138 1.1 135 1.0 177 0.5 medium 148 1.3 131 1.2 172 0.5 Ti / Cu
Dissolution rate ratio 114 109 344

time
(minute) Experimental Example 1
Etching 1 Experimental Example 2
Etching second Experimental Example 3
Etching third H ₂ O ₂ content
(%) H ₂ O ₂ Decomposition Rate
(%) H ₂ O ₂ content
(%) H ₂ O ₂ Decomposition Rate
(%) H ₂ O ₂ content
(%) H ₂ O ₂ Decomposition Rate
(%) 0 24.5 0.0 24.5 0.0 24.5 0.0 30 24.2 1.2 24.2 1.1 24.3 0.8 60 24.0 1.8 23.6 3.8 23.3 4.9 180 23.1 5.5 16.0 34.6 18.4 25.0 300 20.8 14.8 8.4 65.6 13.3 45.5 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

As shown in the results of Experimental Examples 1 to 3, the etchant (etchant 1) of the present invention not only has a high dissolution rate ratio of Ti / Cu but also has a decomposition ratio of hydrogen peroxide after 300 minutes from the start of etching to other etchants (14.8%), which is the lowest in comparison with the etching methods (2) and (3), and the decomposition of hydrogen peroxide is most suppressed (Experimental Example 1). On the other hand, the etchant (etchant 2) of Comparative Example 1 has a dissolution rate ratio of Ti / Cu equal to that of the etchant of the present invention, but the decomposition ratio of hydrogen peroxide is very high, and after 300 minutes Of the hydrogen peroxide was decomposed at about 70% of the hydrogen peroxide (Experimental Example 2). In addition, although the dissolution rate ratio of Ti / Cu was higher than that of the etching agent of the present invention, the decomposition rate of hydrogen peroxide was higher than that of the etching agent of the present invention, and after 300 minutes from the start of etching, And it was found that the neighboring parts were disassembled (Experimental Example 3). Copper (copper oxide) was eluted from the copper plate in any case when the results of the etching rates of copper in Experimental Examples 1 to 3 were taken into account. However, the etching amount by the etching agent of the present invention was the highest in the elution amount of copper (copper oxide) many. Nevertheless, considering that decomposition of hydrogen peroxide is most suppressed in the etchant of the present invention, the phosphonic acid-based chelating agent having a nitrogen atom in the structure, which is a chelating agent according to the present invention, (Chelating) copper (copper oxide) by inhibiting (preventing) the decomposition of hydrogen peroxide.

Example 2: Preparation of the etching agent of the present invention -2

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsu K.K.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching fourth.

Comparative Example 3: Preparation of comparative etching agent-3

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and tartaric acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching fifth.

Comparative Example 4: Preparation of comparative etching agent-4

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and malic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching sixth.

Comparative Example 5: Preparation of comparative etching agent -5

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and 1,2,3-propanetricarboxylic acid (manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 7.

Comparative Example 6: Preparation of comparative etching agent-6

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and benzotriazole (manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 8.

The compositions (components and% by weight) of the etchant of Example 2 and Comparative Examples 3 to 6 are shown in Table 4. [

Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Etching 4 Etching 5 Etching 6 Etching 7 Etching 8 Hydrogen peroxide (% by weight) 24.5 24.5 24.5 24.5 24.5 DEPPO (wt%) 1.8 1.8 1.8 1.8 1.8 Potassium hydroxide (% by weight) 3.0 3.0 3.0 3.0 3.0 Organic acid (copper corrosion inhibitor)
(weight%) Citric acid
0.1 Tartaric acid
0.1 Malian
0.1 1,2,3-propanetricarboxylic acid
0.1 BTA
0.1 Water (% by weight) 70.6 70.6 70.6 70.6 70.6 DEPPO: Diethylene triamine penta (methylene phosphonic acid)
BTA: benzotriazole

EXPERIMENTAL EXAMPLES 4 to 8: Immersion tests of etching agents 4 to 8

Each of the etching agents obtained in Example 2 and Comparative Examples 3 to 6 was placed in a polypropylene container and a 2 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a copper plate (2 cm x 2 cm) Manufactured by Rare Metallic Co., Ltd.) were immersed for two minutes at the same time for 300 minutes. During the etching, 100 袖 L was sampled for each of the metal contents (100, 60, 120, 180, 240, and 300 minutes) and 100 袖 L for the hydrogen peroxide analysis.

Each of the sampled etchants used for analyzing the metal content was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the amounts of dissolution of metallic titanium and metallic copper per unit area of the titanium plate and copper plate, and the etching rates of titanium and copper were calculated. The results are shown in Table 5.

Each of the etching agents sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method with 0.02 mol / L potassium permanganate. The results are shown in Table 6.

These experiments were carried out by immersing two titanium plates and copper plates continuously for a maximum of 300 minutes for a maximum of 300 minutes. In this experimental example, when using an actual etching agent, a model experiment in which a method of continuously immersing a plurality of semiconductor substrates , And the etch rate and the decomposition rate of hydrogen peroxide when the same etchant was continuously used for etching a plurality of semiconductor substrates for a maximum of 300 minutes.

time
(minute)
Experimental Example 4
Etching 4 Experimental Example 5
Etching 5 Experimental Example 6
Etching 6 Experimental Example 7
Etching 7 Experimental Example 8
Etching 8 Ti E / R
(nm /
min.) Cu E / R
(nm /
min.) Ti E / R
(nm /
min.) Cu E / R
(nm /
min.) Ti E / R
(nm /
min.) Cu E / R
(nm /
min.) Ti E / R
(nm /
min.) Cu E / R
(nm /
min.) Ti E / R
(nm /
min.) Cu E / R
(nm /
min.) 60 61 0.0 65 0.7 62 0.6 66 0.7 63 0.0 120 61 0.3 67 0.7 63 0.7 67 0.8 66 0.0 180 64 0.6 71 0.8 65 0.8 70 0.9 67 0.1 240 62 0.6 71 0.9 66 0.9 72 1.0 68 0.3 300 64 0.7 77 1.0 70 1.0 74 1.0 76 0.9 medium 62 0.4 70 0.8 65 0.8 70 0.9 68 0.3 Ti / Cu
Dissolution
Speed ratio 155 88 81 78 227

time
(minute) Experimental Example 4
Etching 4 Experimental Example 5
Etching 5 Experimental Example 6
Etching 6 Experimental Example 7
Etching 7 Experimental Example 8
Etching 8 H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) 0 24.5 0.0 24.5 0.0 24.5 0.0 24.5 0.0 24.5 0.0 60 24.3 0.8 24.2 1.2 24.4 0.4 24.3 0.8 24.3 0.8 120 24.0 2.0 23.8 2.9 23.9 2.4 23.7 3.3 24.1 1.6 180 23.9 2.4 23.5 4.1 23.3 4.9 23.1 5.7 23.4 4.5 240 23.6 3.7 22.7 7.3 21.9 10.6 22.2 9.4 21.8 11.0 300 22.6 7.8 21.1 13.9 20.9 14.7 20.4 16.7 19.0 22.4 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

As shown in the results of Experimental Examples 4 to 8, the etchant (etchant 4) of the present invention has the lowest decomposition rate of hydrogen peroxide after 300 minutes from the start of etching compared with other etchants (etchants 5 to 8) 7.8%, indicating that the decomposition of hydrogen peroxide is most suppressed (Experimental Example 4). From the results of the etching rates of copper in Experimental Examples 4 to 7, it was found that when the etching agent was used for a long time, the etching by the etching agent of the present invention suppressed the amount of copper (copper oxide) elution from the copper plate. In view of these points, an organic acid (copper corrosion inhibitor) having at least one hydroxyl group and at least three carboxyl groups as the organic acid (copper corrosion inhibitor) according to the present invention among the organic acids (copper corrosion inhibitors) (Copper oxide) can be suppressed most effectively, and further, the decomposition of hydrogen peroxide by copper (copper oxide) is suppressed. Further, in comparison with an etchant containing a benzotriazole as a conventionally known copper corrosion inhibitor (etchant 8), when the etchant is continuously used for a long time, the decomposition of hydrogen peroxide is suppressed in the etchant of the present invention .

Comparative Example 7: Preparation of comparative etching agent-7

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and benzotriazole (manufactured by Wako Pure Chemical Industries, Ltd.) were added and stirred appropriately to obtain a comparative etching agent. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching No. 9.

Comparative Example 8: Preparation of Comparative Etching Agent-8

(Produced by Wako Pure Chemical Industries, Ltd.), ethylenediamine (manufactured by Wako Pure Chemical Industries, Ltd.), potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsuya Kogyo Co., Ltd.) were added to ultrapure water, However, since the hydrogen peroxide and ethylenediamine reacted violently and the hydrogen peroxide was rapidly decomposed, the comparative etching solution 10 could not be obtained.

Comparative Example 9: Preparation of Comparative Etching Agent-9

(Manufactured by Wako Pure Chemical Industries, Ltd.), ethanolamine (manufactured by Wako Pure Chemical Industries, Ltd.), potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsuya Kogyo Co., Ltd.) were added to ultrapure water, , Hydrogen peroxide and ethanolamine reacted violently and the hydrogen peroxide was rapidly decomposed, so that the comparative etching 11 could not be obtained.

The compositions (components and% by weight) of the etchants of Comparative Examples 7 to 9 are shown in Table 7 together with the composition of the etchant of Example 1.

Example 1 Comparative Example 7 Comparative Example 8 Comparative Example 9 Etching 1 Etching 9 Etching 10 Etching 11 Hydrogen peroxide (% by weight) 24.5 24.5 24.5 24.5 Chelating agent
(weight%) DEPPO
1.5 DEPPO
1.5 Ethylenediamine
1.5 Ethanolamine
1.5 Potassium hydroxide (% by weight) 3.0 3.0 3.0 3.0 Organic acid (copper corrosion inhibitor)
(weight%) Citric acid
0.1 BTA
0.1 Citric acid
0.1 Citric acid
0.1 Water (% by weight) 70.9 70.9 70.9 70.9 DEPPO: Diethylene triamine penta (methylene phosphonic acid)
BTA: benzotriazole

Experimental Example 9: Immersion test of Etching Ninth

The etching agent obtained in Comparative Example 7 was placed in a container made of polypropylene, and a 1 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a copper plate of 2 cm x 2 cm (manufactured by Rare Metallic Co., Ltd.) And immersed for 300 minutes at the same time. During the etching, 100 μL was sampled at predetermined times (30, 60, 180, 300 minutes) for analyzing the metal content and 100 μL was sampled for analysis of hydrogen peroxide.

The sampled etchant for metal content analysis was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus name: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the amount of dissolution of titanium metal and copper metal per unit area of the titanium plate and the copper plate, and the etching rate of titanium and copper were calculated. The results are shown in Table 8 together with the results of Experimental Example 1.

The etching agent sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method using 0.02 mol / L potassium permanganate. The results are shown in Table 9 together with the results of Experimental Example 1.

The present experimental example is an experiment in which a titanium plate and a copper plate are continuously immersed in a single sheet for a maximum of 300 minutes. In this experiment, a model experiment in which a method of continuously immersing a plurality of semiconductor substrates at the time of using an actual etching agent , And the etching rate and the decomposition rate of hydrogen peroxide when the same etching agent was continuously used for etching a plurality of semiconductor substrates for a maximum of 300 minutes.

time
(minute) Experimental Example 1
Etching 1 Experimental Example 9
Etching 9 Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) 30 158 1.8 151 0.0 60 145 1.2 153 0.4 180 149 1.0 160 0.7 300 138 1.1 165 1.5 medium 148 1.3 157 0.7 Ti / Cu dissolution rate ratio 114 241

time
(minute) Experimental Example 1
Etching 1 Experimental Example 9
Etching 9 H ₂ O ₂ content
(%) H ₂ O ₂ Decomposition Rate
(%) H ₂ O ₂ content
(%) H ₂ O ₂ Decomposition Rate
(%) 0 24.5 0.0 24.5 0.0 30 24.2 1.2 24.4 0.4 60 24.0 1.8 24.1 1.6 180 23.1 5.5 22.1 9.8 300 20.8 14.8 17.6 28.2 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

The etchant (etchant 9) of Experimental Example 9 was obtained in the same manner as in Example 8 except that the content of diethylenetriamine penta (methylenephosphonic acid), which is a chelating agent according to the present invention, was 0.3 wt% %, And it was confirmed to what extent the elution amount of copper (copper oxide) from the copper plate affected the decomposition of hydrogen peroxide. As can be seen from the results of Experimental Examples 1 and 9, as compared with the conventionally known etchant containing benzotriazole (etchant 9) which is a copper corrosion inhibitor, the etchant of the present invention (etchant 1) The total elution amount of copper (copper oxide) from the copper plate on the etching side increases. From the viewpoint of the corrosion-preventing effect of the copper corrosion inhibitor, since the kinds of copper corrosion inhibitors differ only in the etchant (etchant 1) of the present invention and the etchant (etchant 9) of Experimental Example 9 in Experimental Example 1, The dissolution amount of copper (copper oxide) from the copper plate is smaller on the etching side by the etching agent (etching agent 9) of Experimental Example 9, so that decomposition of hydrogen peroxide is suppressed. However, as can be seen from the results of Table 9, rather than the etchant of the present invention (etchant 1) of Experimental Example 1, the etchant of Experimental Example 9 (etchant 9) The result is that it is proceeding at the speed of the ship. Although the details are unclear, it is suggested that benzotriazole has an adverse effect on hydrogen peroxide. The inhibition of hydrogen peroxide decomposition can be suppressed only by inhibiting elution of copper (copper oxide) from metal copper or copper alloy . As can be seen from the results of Comparative Examples 8 and 9, in the etchant containing ethylenediamine (etchant 10) and the etchant containing etanolamine (etchant 11), which are known chelating agents, these chelating agents are hydrogen peroxide And the hydrogen peroxide was rapidly decomposed. From these results, the copper corrosion inhibitor is not effective in suppressing the elution of copper (copper oxide) from metallic copper or copper alloy, and does not adversely affect hydrogen peroxide, but copper from copper or copper alloy The chelating agent should be one which can effectively inhibit the elution of copper (copper), and that the chelating agent is not any good as long as it can capture (chelate) copper (copper oxide), but does not adversely affect hydrogen peroxide Copper) to be effectively captured (chelated). From the above fact, it is necessary to select the organic acid according to the present invention such as citric acid as the copper corrosion inhibitor in order to selectively etch the Ti-based metal while suppressing the decomposition of the hydrogen peroxide. As the chelating agent, It was found that there was a need to select a chelating agent.

Examples 3 to 6: Formulation of etching agent of the present invention -3 to 6

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (manufactured by Itarmak Japan Co., Ltd.) and potassium hydroxide Manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsu Co., Ltd.) were added and stirred appropriately to obtain the etching agent of the present invention. The obtained etchant had a pH of 9.0. This etching agent was designated as Etching Nos. 12 to 15.

The compositions (components and% by weight) of the etching agents of Examples 3 to 6 are shown in Table 10.

Example 3 Example 4 Example 5 Example 6 Etching 12 Etching 13 Etching 14 Etching 15 Hydrogen peroxide (% by weight) 24.5 24.5 24.5 24.5 DEPPO (wt%) 0.4 0.5 0.6 0.8 Potassium hydroxide (% by weight) 3.0 3.0 3.0 3.0 Citric acid (% by weight) 0.1 0.1 0.1 0.1 Water (% by weight) 72.0 71.9 71.8 71.6  DEPPO: Diethylene triamine penta (methylene phosphonic acid)

EXPERIMENTAL EXAMPLES 10 TO 13: Immersion tests of the etching agents 12 to 15

Each of the etching agents obtained in Examples 3 to 6 was placed in a container made of polypropylene and a 1 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a copper plate (manufactured by Rare Metallic Co., 2 cm x 2 cm) Were immersed for one hour at the same time for 300 minutes. During the etching, 100 μL for analyzing the metal content and 100 μL for the hydrogen peroxide analysis were sampled at predetermined time intervals (30, 60, 180, and 300 minutes), respectively.

Each of the sampled etchants used for analyzing the metal content was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the amounts of dissolution of titanium and copper and the etching rates of titanium and copper per unit area of the titanium plate and copper plate were calculated. The results are shown in Table 11.

Each of the etching agents sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method using 0.02 mol / L potassium permanganate. The results are shown in Table 12.

These experiments were conducted by immersing the titanium plate and the copper plate one by one for a maximum of 300 minutes for a maximum of 300 minutes. In this experimental example, when using an actual etching agent, a model experiment in which a method of continuously immersing a plurality of semiconductor substrates , And the etch rate and the decomposition rate of hydrogen peroxide when the same etchant is continuously used for a maximum of 300 minutes by etching a plurality of semiconductor substrates.

time
(minute) Experimental Example 10
Etching 12 Experimental Example 11
Etching 13 Experimental Example 12
Etching 14 Experimental Example 13
Etching 15 Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) 30 145 0.0 168 0.0 165 0.0 154 0.0 60 151 0.0 168 0.2 168 0.3 159 0.3 180 159 0.3 177 0.4 183 0.5 176 0.6 300 173 0.3 178 0.4 189 0.6 176 0.7 medium 157 0.1 173 0.3 176 0.4 166 0.4 Ti / Cu dissolution rate ratio 1209 686 502 442

time
(minute) Experimental Example 10
Etching 12 Experimental Example 11
Etching 13 Experimental Example 12
Etching 14 Experimental Example 13
Etching 15 H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) 0 24.5 0.0 24.5 0.0 24.5 0.0 24.5 0.0 30 24.4 0.4 24.5 0.0 24.5 0.0 24.4 0.4 60 24.2 1.2 24.4 0.4 24.4 0.4 24.4 0.4 180 23.6 3.7 24.0 2.0 24.2 1.2 24.2 1.2 300 21.7 11.4 22.0 10.2 22.1 9.8 22.3 9.0 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

As shown in the results of Experimental Examples 10 to 13, it was found that the decomposition of hydrogen peroxide by copper (copper oxide) can be suppressed as the content of the chelating agent according to the present invention is increased. It was also found that etching with any etching agent has a high dissolution rate ratio of Ti / Cu and can suppress the decomposition of hydrogen peroxide.

Example 7: Preparation of the etching agent of the present invention-7

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (Itarmaki Japan Co., Ltd.), sodium hydroxide Ltd.) and citric acid (manufactured by Komatsu K. K.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.2. This etching agent was designated as etching No. 16.

Example 8: Preparation of the etching agent of the present invention-8

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (Itarmaki Japan Co., Ltd.), sodium hydroxide Ltd.) and citric acid (manufactured by Komatsu K. K.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 17.

Example 9: Preparation of the etching agent of the present invention-9

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (Itarmaki Japan Co., Ltd.), lithium hydroxide Ltd.) and citric acid (manufactured by Komatsu K. K.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 18.

The compositions (components and% by weight) of the etchants of Examples 7 to 9 are shown in Table 13 together with the composition of the etchant of Example 1.

Example 1 Example 7 Example 8 Example 9 Etching 1 Etching 16 Etching 17 Etching 18 Hydrogen peroxide (% by weight) 24.5 24.5 24.5 24.5 DEPPO (wt%) 1.5 1.5 1.5 1.5 Alkali metal hydroxide
(weight%) KOH
3.0 NaOH
3.0 NaOH
2.8 LiOH
1.7 Citric acid (% by weight) 0.1 0.1 0.1 0.1 Water (% by weight) 70.9 70.9 71.1 72.2 pH 9.0 9.2 9.0 9.0 DEPPO: Diethylene triamine penta (methylene phosphonic acid)
KOH: Potassium hydroxide
NaOH: Sodium hydroxide
LiOH: lithium hydroxide

EXPERIMENTAL EXAMPLES 14 to 16: Immersion test of etching agents 16 to 18

Each of the etching agents obtained in Examples 7 to 9 was placed in a polypropylene container, and a 1 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a copper plate (manufactured by Rare Metallic Co., Ltd.) of 2 cm x 2 cm Each one of them was dipped for 300 minutes at the same time. During the etching, 100 μL for analyzing the metal content and 100 μL for the hydrogen peroxide analysis were sampled at predetermined time intervals (30, 60, 180, and 300 minutes), respectively.

Each of the sampled etchants used for analyzing the metal content was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the amounts of dissolution of titanium and copper and the etching rates of titanium and copper per unit area of the titanium plate and copper plate were calculated. Table 14 shows the results.

Each of the etching agents sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method using 0.02 mol / L potassium permanganate. Table 15 shows the results.

These experiments were conducted by immersing the titanium plate and the copper plate one by one for a maximum of 300 minutes for a maximum of 300 minutes. In this experimental example, when using an actual etching agent, a model experiment in which a method of continuously immersing a plurality of semiconductor substrates , And the etch rate and the decomposition rate of hydrogen peroxide when the same etchant is continuously used for a maximum of 300 minutes by etching a plurality of semiconductor substrates.

time
(minute) Experimental Example 1
Etching 1 Experimental Example 14
Etching 16 Experimental Example 15
Etching 17 Experimental Example 16
Etching 18 Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) 30 158 1.8 311 0.5 219 0.3 166 0.0 60 145 1.2 309 0.5 214 0.4 173 0.0 180 149 1.0 343 0.7 242 0.5 187 0.0 300 138 1.1 340 0.8 235 0.5 191 0.0 medium 148 1.3 326 0.6 227 0.4 179 0.0 Ti / Cu dissolution rate ratio 114 532 581 11883

time
(minute) Experimental Example 1
Etching 1 Experimental Example 14
Etching 16 Experimental Example 15
Etching 17 Experimental Example 16
Etching 18 H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) 0 24.5 0.0 24.5 0.0 24.5 0.0 24.5 0.0 30 24.2 1.2 24.4 0.4 24.2 1.2 24.4 0.4 60 24.0 1.8 24.0 2.0 23.8 2.9 24.3 0.8 180 23.1 5.5 23.0 6.1 23.3 4.9 23.4 4.5 300 20.8 14.8 20.7 15.5 21.6 11.8 22.7 7.3 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

Among the alkali metal hydroxides according to the present invention, as shown in the results of Experimental Examples 1 and 14 to 16, the etching rate of titanium by the etching agent containing the lithium hydroxide and sodium hydroxide (the etching agents 16 to 18) And a high Ti / Cu dissolution rate ratio as a result. It was also found that this etching agent can suppress decomposition of hydrogen peroxide to the same degree or less as compared with an etching agent containing potassium hydroxide (etching first). From these results, it was found that among the alkali metal hydroxides according to the present invention, lithium hydroxide and sodium hydroxide were preferable alkali metal hydroxides.

Example 10: Preparation of etching agent of the present invention-10

To the ultrapure water, hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), diethylenetriamine penta (methylenephosphonic acid) hepta sodium salt (32% aqueous solution) (Itarmakatch Japan Co., Ltd.), potassium hydroxide Ltd.) and citric acid (manufactured by Komatsu K. K.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching No. 19.

Example 11: Preparation of the etching agent of the present invention-11

(Manufactured by Wako Pure Chemical Industries, Ltd.), ethylenediamine tetra (methylenephosphonic acid) (manufactured by Dong Kurn Co., Ltd.), potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid Manufactured by Komatsu Kogyo Co., Ltd.) was added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 20.

Example 12: Preparation of the etching agent of the present invention -12

(Manufactured by Wako Pure Chemical Industries, Ltd.), nitrilotris (methylenephosphonic acid) (50% aqueous solution) (manufactured by Tokyo Chemical Industry Co., Ltd.), potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) And citric acid (manufactured by Komatsu Co., Ltd.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 21.

Comparative Example 10: Preparation of Comparative Etching Agent-10

Hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.), 1-hydroxyethane-1,1-bis (phosphonic acid) (60% aqueous solution) (manufactured by Wako Pure Chemical Industries, Ltd.) was added to ultrapure water, Potassium hydroxide (manufactured by Wako Pure Chemical Industries, Ltd.) and citric acid (manufactured by Komatsu Co., Ltd.) were added and stirred appropriately to obtain an etching agent of the present invention. The pH of the obtained etching agent was 9.0. This etching agent was designated as etching 22.

The compositions (components and% by weight) of the etching agents of Examples 10 to 12 and Comparative Example 10 are shown in Table 16.

Example 10 Example 11 Example 12 Comparative Example 10 Etching 19 Etching 20 Etching 21 Etching 22 Hydrogen peroxide (% by weight) 24.5 24.5 24.5 24.5 Chelating agent
(weight%) DEPPO
1.5 EDTPO
1.5 NTPO
1.5 HEDPO
1.5 Potassium hydroxide (% by weight) 3.0 3.0 3.0 3.0 Citric acid
(weight%) 0.1 0.1 0.1 0.1 Water (% by weight) 70.9 70.9 70.9 70.9 DEPPO: Diethylene triamine penta (methylene phosphonic acid)
EDTPO: Ethylenediaminetetra (methylenephosphonic acid)
NTPO: Nitrile tris (methylenephosphonic acid)
HEDPO: 1-hydroxyethane-1,1-bis (phosphonic acid)

Experimental Examples 17 to 20: Immersion tests of Etching Agents 19 to 22

Each of the etching agents obtained in Examples 10 to 12 and Comparative Example 10 was placed in a container made of polypropylene, and a 3 cm x 2 cm titanium plate (manufactured by Rare Metallic Co., Ltd.) and a 4 cm x 2 cm copper plate Manufactured by Metallic Co., Ltd.) were immersed for one hour at the same time for 300 minutes. During the etching, 100 μL for analyzing the metal content and 100 μL for the hydrogen peroxide analysis were sampled at predetermined time intervals (30, 60, 180, and 300 minutes), respectively.

Each of the sampled etchants used for analyzing the metal content was diluted 100 times with 1% nitric acid aqueous solution, and the content of metallic titanium and metallic copper was measured by a plasma emission spectrometer (apparatus: ICP-AES SPS-3100; manufactured by SII). From the results of the measured contents, the dissolution amount of titanium metal and copper metal per unit area of the titanium plate and copper plate, and the etching rate of titanium and copper were calculated. The results are shown in Table 17.

Each of the etching agents sampled for the hydrogen peroxide analysis was mass-up to 10 mL with a 0.5N sulfuric acid aqueous solution, and the content of hydrogen peroxide was calculated by an oxidation-reduction titration method using 0.02 mol / L potassium permanganate. The results are shown in Table 18.

These experiments were conducted by immersing the titanium plate and the copper plate one by one continuously for a maximum of 300 minutes, and compared with the experimental conditions of Experimental Examples 1 to 16, the area of the titanium plate was changed from 1.5 times to 3 times, 2 times. This experimental example is a model experiment under harsh conditions than the actual etching agent, and confirms the difference in the hydrogen peroxide decomposition inhibiting effect due to the difference of the chelating agent.

time
(minute) Experimental Example 17
Etching 19 Experimental Example 18
Etching 20 Experimental Example 19
Etching 21 Experimental Example 20
Etching 22 Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) Ti E / R
(nm / min.) Cu E / R
(nm / min.) 30 139 1.7 93 0.5 106 2.3 118 2.4 60 151 1.4 112 0.5 107 1.9 138 2.1 180 164 1.3 120 0.3 114 1.7 - - 300 147 1.3 139 0.3 118 1.6 - - medium 150 1.4 116 0.4 111 1.9 - - Ti / Cu dissolution rate ratio 106 301 59 -

time
(minute) Experimental Example 17
Etching 19 Experimental Example 18
Etching 20 Experimental Example 19
Etching 21 Experimental Example 20
Etching 22 H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) H ₂ O ₂
content
(%) H ₂ O ₂
Decomposition rate
(%) 0 24.5 0.0 24.5 0.0 24.5 0.0 24.5 0.0 30 24.5 0.0 24.4 0.4 24.3 0.8 24.0 2.0 60 24.3 0.8 24.2 1.2 24.3 0.8 20.5 16.3 180 23.6 3.7 22.5 8.2 24.1 1.6 0.0 100.0 300 17.2 29.8 14.8 39.6 19.7 19.6 0.0 100.0 H ₂ O ₂ decomposition rate (etch 0 minutes H ₂ O ₂ content (%) - H ₂ O ₂ content of the respective time (%) / etch 0 minutes H ₂ O ₂ content (%)) × 100

As shown in the results of Experimental Examples 17 to 19, among the chelating agents according to the present invention, an etchant containing diethylene triamine penta (methylene phosphonic acid) (etchant 19) and nitrile tris (Etchant 21) containing nitrilotris (methylenephosphonic acid) is preferable, and that an etchant containing nitrilotris (methylenephosphonic acid) (etchant 21) can suppress decomposition of hydrogen peroxide the most there was. In addition, as shown in the results of Experimental Example 20, when this etching agent is continuously used for a long time in an etching agent containing a phosphonic acid chelating agent having no nitrogen atom in the structure (etching agent 22), hydrogen peroxide is rapidly decomposed It was found that it was difficult to continue use for a long time.

From the above results, it can be seen that only the etching agent of the present invention in which (B) a phosphonic acid chelating agent having a nitrogen atom in its structure and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups are combined, It is possible to suppress (prevent) the decomposition of the hydrogen peroxide without lowering the dissolution rate ratio of the hydrogen peroxide solution. As a result, the life of the solution is prolonged. In addition, since the etching agent of the present invention has an appropriate etching rate, it can be seen that the etching agent is easy to control the etching rate.

The etching agent of the present invention is an etching agent used for processing a Ti-based metal in a semiconductor substrate having a Ti-based metal and a Ti-based metal, more particularly, a semiconductor substrate having a metal- Is a preferable etching agent for the Ti-based metal.

The etching method of the present invention is an etching method suitable for Ti-based metal processing in a semiconductor substrate having a Ti-based metal, and more particularly, to a method for etching a Ti-based metal on a semiconductor substrate having a Ti-based metal and a metallic copper or copper alloy on the Ti- Ti-based metal.

The etching solution of the present invention can be used as the etching solution of the present invention by mixing with a solution containing hydrogen peroxide, and is a preparation solution suitable for the preparation of the etching solution of the present invention.

Claims (18)

1. An aqueous solution containing at least the following (A), (B), (C) and (D): an aqueous solution containing titanium metal and an etchant for titanium metal on a semiconductor substrate having a metal copper or copper alloy on top of the titanium metal My.
(A) hydrogen peroxide
(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure
(C) an alkali metal hydroxide
(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups The method according to claim 1,
Wherein the etchant has a pH range of 7 to 10. The method according to claim 1,
(A) a content of a phosphonic acid chelating agent having a nitrogen atom in the structure of 0.05 to 5% by weight, (C) an alkali metal hydroxide in an amount of 0.2 to 5% by weight, (B) , And (D) 0.01 to 5% by weight of an organic acid having at least one hydroxyl group and at least three carboxyl groups. The method according to claim 1,
(B) A phosphonic acid chelating agent having a nitrogen atom in its structure is nitrilotris (methylenephosphonic acid), ethylenediaminetetra (methylenephosphonic acid), or diethylenetriamine penta (methylenephosphonic acid). The method according to claim 1,
(B) an etching agent in which a phosphonic acid-based chelating agent having a nitrogen atom in its structure is nitrilotris (methylenephosphonic acid). The method according to claim 1,
(C) the alkali metal hydroxide is selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide and cesium hydroxide. The method according to claim 1,
(C) an alkali metal hydroxide is lithium hydroxide or sodium hydroxide. The method according to claim 1,
(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups is citric acid. The method according to claim 1,
Wherein the aqueous solution consists essentially of (A), (B), (C) and (D). The method according to claim 1,
(B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide, and (D) an organic acid having at least one hydroxyl group and at least three carboxyl groups Wherein the etching solution is an aqueous solution containing an organic solvent. The method according to claim 1,
(B) a phosphonic acid chelating agent having a nitrogen atom in its structure, (C) an alkali metal hydroxide (C) in an amount of 4 to 10 wt.%, And 0.2 to 10% by weight of (D) an aqueous solution containing an organic acid having at least one hydroxyl group and at least three carboxyl groups are mixed at a mixing ratio of 50: 50 to 95: 5 on a weight basis Etching agent to be prepared. A method for manufacturing a semiconductor device comprising the steps of: using an etching agent which is an aqueous solution containing at least the following (A), (B), (C) and (D) Titanium-based metal is selectively etched.
(A) hydrogen peroxide
(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure
(C) an alkali metal hydroxide
(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups 13. The method of claim 12,
Wherein the pH of the etchant ranges from 7 to 10. 13. The method of claim 12,
Wherein the titanium-based metal has a layered structure or a film-like structure, and the metallic copper or copper alloy has a film-like structure, a wiring structure or a bump-like structure. (A) an aqueous solution containing at least the following (B), (C) and (D), and further comprising (A) a solution containing hydrogen peroxide, wherein the titanium-based metal and the titanium- An etching solution for preparing an etching agent for a titanium-based metal on a semiconductor substrate having an alloy.
(B) a phosphonic acid-based chelating agent having a nitrogen atom in its structure
(C) an alkali metal hydroxide
(D) an organic acid having at least one hydroxyl group and at least three carboxyl groups 16. The method of claim 15,
(C) the content of the alkali metal hydroxide is 4 to 10% by weight, and (D) the content of the phosphonic acid chelating agent having at least one hydroxyl group and at least one hydroxyl group Wherein the content of the organic acid having three carboxyl groups is 0.2 to 10% by weight. 17. The method of claim 16,
(A) 20 to 35% by weight of a solution containing hydrogen peroxide to prepare an etching agent. 18. The method of claim 17,
(A) a solution containing hydrogen peroxide in a weight ratio of 50:50 to 95: 5.